Today’s internet is rich with all kinds of multimedia from image galleries to audio and video streaming to real-time dynamic interactive content.
Where to start with multimedia and accessibility
The first step is to determine what exactly is it you want to achieve. What I mean by this is the message or communication interaction you want to convey between yourself and your visitors.
Say for example, if you are giving a video tutorial on a product, think about the information within that video. Not just what may be spoken but any visual information. It is this that can create your full video transcript.
Then think about your audience, all the different assistive technologies and how people will interact with your web content. From this you can decide about using audio description or signing or captioning within your video.
Lastly before you start work on creating any of these things, think about, progressive enhancement, what will work everywhere?
Next steps in multimedia and accessibility
Using this video example, the one thing that will work with all assistive technology and all browsers, from the things outlined above is your full video transcript. This is because transcripts are typically text based and if any images are included, they should have text alternatives.
So following the progressive enhanced design principles your full transcript will be the default content. Then you can test for video support and if used, support for captioning or other features added to your video. If your video is supported by the visitors browser of choice, you can then show the video and replace the default transcript content with a link to the transcript. This way keeping the choice of a transcript for your visitor, if that is their preferred format.
What about other media content?
Audio will work much the same as video by having a full text transcript. Flash, silverlight or similar content will generally have their own set of accessibility guidelines but again, having a text based version of the information, will allow for cases where the support is not available.
Document links should indicate within the link text what the document format is and optionally its size. It is not required for you to make the same document available in multiple formats to suit individuals personal preference. However, whichever format you choose to use, you should follow any published accessibility guidelines for it.
Charts, diagrams and other visual illustrations are one that can give people with a visual impairment, accessibility problems. This can generally be addressed through text based descriptions and tabular data that relates to the charts. This is one area that work is currently being done in, to try and make use of a mix of sound, tactile and text to speech to help enhance accessibility.
How about real-time dynamic content?
This is typically done with Javascript, so the first step will be to create some kind of basic text alternative. Before checking that the browser being used has support for your content. Then you can apply basic accessibility principles to how your real-time dynamic content is created and interactive with. Things like device independence.
For modern browsers, you can use HTML5 and ARIA. This allows you to specify additional information that assistive technology can use helping to make the content more accessible. Again, giving the user the option to choose the default basic content, will empower them with the freedom of choice.
Wrapping it all up
Rich multimedia content does add to the accessibility requirements but given some thought prior to adding your multimedia, it can still be kept accessible to everyone.
Understanding how people use assistive technology and how they interact with websites plus following key principles of accessibility, it can really help you make a difference.